As long as Rocket's Entei ex has any Energy attached to it, Rocket's Entei ex has no Weakness.
Energy Link エンジーコネクター
10
Search your discard pile for an Energy card and attach it to Rocket's Entei ex.
Volcanic Ash かさいりゅう
Discard 2 Energy attached to Rocket's Entei ex and then choose 1 of your opponent's Pokémon. This attack does 60 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)
Trivia
If this card were to follow the normal TCG type rules, it would be a card.